Aircraft include environmental control systems that condition and filter the air to supply to occupied interior spaces which house passengers, crew, and/or electronic equipment. Hereafter, such occupied interior spaces shall be collectively referred to as the “cabin.” The environmental control system controls cabin temperature by regulating the temperature of the air supplied to the cabin. The air temperature supplied to the cabin is regulated, at least in part, by utilizing air from the exterior of the aircraft which passes through one or more heat exchangers in the environmental control system.
Aircraft operate in various geographical areas, including those with elevated levels of pollution. Pollutants include particulates, such as dust and ash, and compounds such as sulfur oxides, nitrogen oxides, carbon monoxide, and volatile organic compounds. Over time, pollutants accumulate in the environmental control system, and particularly in the heat exchanger. Over time the accumulated pollutants reduce the heat transfer efficiency of the one or more heat exchangers. Other components in the environmental control may have to work harder to provide the desired temperature air to the cabin; this undermines the reliability of such other components. Also, the pollutants may corrode the one or more heat exchangers and possibly other components of the environmental control system. As a result, the environmental control system becomes more inefficient and unreliable. This can lead to occupant discomfort in the cabin.
Because of pollution, environmental control system components, such as the one or more heat exchangers, must be periodically serviced or replaced. Such maintenance increases cost, not only due to the maintenance, but also because the aircraft is out of service. Accordingly, it is desirable to increase the time period between such maintenance.